The present invention is directed, in general, to automated test systems and, more specifically, to a system for the automated testing of digital television receivers.
In recent years significant efforts have been made to develop objective, quantitative techniques for measuring the quality of visual images. The algorithms that have resulted from these efforts have been primarily used to test the performance of image processing equipment and to analyze faults within the equipment. The specific technique utilized for analyzing the image quality of a particular system depends not only upon the characteristics of the image but also upon the technology used to generate the image.
While objective and quantitative image measurement techniques were evolving, new types of technology were also being developed to transfer digital images from a transmitting station, such as a television station, to one or more remotely located receiving stations, such as digital television receivers. These developments eventually resulted in the Advanced Television Systems Committee (ATSC) adopting voluntary standards for advanced television technology. The ATSC standard was accepted by the Federal Communications Commission (FCC) in November 1995. The ATSC standard became the basis for the United States digital television standard that was formally accepted in December 1996. The ATSC standard incorporates the Moving Pictures Experts Group (MPEG) compression scheme for full motion video with audio. Most current digital high definition television (HDTV) systems utilize the MPEG2 standard. Newer HDTV systems will use the MPEG4 standard in the future. MPEG2 and MPEG4 offer a wide range of compression ratios with varying degrees of audio and video quality.
The first broadcast of HDTV in the United States utilizing the ATSC standard occurred in November 1998. It is presently planned that all television broadcasts within the United States will use digital HDTV television signals by the year 2006. The evolution of HDTV has resulted in development of several new technologies for the encoding, transmission, reception, decoding and display of digital video images.
However, present manufacturing, testing and diagnostic techniques are not designed to adequately and objectively assess the quality of digital video images. The relatively recent development of digital television technology has created a demand for better and more efficient digital video image testing and diagnostic equipment.
There is therefore a need for a system and method for testing digital television receivers. In particular, there is a need for a system and method for an automated test system for digital television receivers. More particularly, there is a need in the art for an improved system and method for an automated test system for digital television receivers that provides an objective quantitative analysis of the quality of digital video images.
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide an improved system and method for the automated testing of digital television receivers.
The system and method of the present invention comprises a digital video signal unit capable of sending an encoded digital video test pattern to a digital television receiver. The digital video signal unit is capable of receiving from the digital television receiver a decoded reconstructed digital video signal representing the digital video test pattern as displayed by the digital receiver television receiver.
The automated test system also comprises a test processing unit that is capable of comparing the digital video test pattern with the reconstructed digital video signal to determine the video quality of operation of the digital television receiver. The system and method of the present invention compares the digital video test pattern and the reconstructed digital video signal by 1) comparing the amount of jitter, and 2) comparing the signal to noise ratio, and 3) computing percentage similarity between image blocks for the two video signals.
It is an object of the present invention to provide an automated test system for digital television receivers capable of sending a digital video test pattern to a digital television receiver and capable of receiving a reconstructed digital video signal representing the digital video test pattern as displayed by the digital television receiver.
It is also an object of the present invention to provide an automated test system for digital television receivers capable of comparing a digital video test pattern with a reconstructed digital video signal to determine the video quality of operation of a digital television receiver.
It is another object of the present invention to provide an automated test system for digital television receivers capable of comparing the amount of jitter in a reconstructed digital video signal with a digital video test pattern to determine the video quality of operation of a digital television receiver.
It is still another object of the present invention to provide an automated test system for digital television receivers capable of comparing the signal to noise ratio in a reconstructed digital video signal with a digital video test pattern to determine the video quality of operation of a digital television receiver.
It is an additional object of the present invention to provide an automated test system for digital television receivers capable of computing percentage similarity between an image block in a reconstructed digital video signal and an image block in a digital video test pattern to determine the video quality of operation of a digital television receiver.
The foregoing has outlined rather broadly the features and technical advantages of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
Before undertaking the DETAILED DESCRIPTION, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms xe2x80x9cincludexe2x80x9d and xe2x80x9ccomprise,xe2x80x9d as well as derivatives thereof, mean inclusion without limitation; the term xe2x80x9cor,xe2x80x9d is inclusive, meaning and/or; the phrases xe2x80x9cassociated withxe2x80x9d and xe2x80x9cassociated therewith,xe2x80x9d as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term xe2x80x9ccontrollerxe2x80x9d means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.